A torsional potential for graphene derived from fitting to DFT resultsGeorgios D. Chatzidakis, George Kalosakas, Zacharias G. Fthenakis and Nektarios N. LathiotakisEur. Phys. J. B, 91 1 (2018) 11DOI: https://doi.org/10.1140/epjb/e2017-80444-5